Circuit breaker



United lStates Patent GP CIRCUIT BREAKER Samuel A. Bottonari,Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application August 30,1957, Serial No. 681,215

' 3 Claims. (Cl. 200-148) This invention relates to circuit breakers andmore particularly to means for controlling rebound ofthe moving contactstructure.

An object of the invention is to provide a circuit breaker embodying amovable contact structure movable at high speed with means forpreventing rebound of the moving Contact structure.

Another object of the invention is to provide a circuit breakerembodying a high-speed movable contact structure with means preventingrebound of the contact structure when it is suddenly stopped in itsopening movement.

The invention both as to structure and operation together withadditional objects and advantages thereof, will be best understood fromthe following detailed description thereof, when read in conjunctionwith the accompanying drawing which comprises an elevational view,partly in section, of a circuit breaker embodying the principles of theinvention.

Referring to the single figure ofthe drawing, the circuit breakercomprises generally a plurality of pole units (only one being shown)mounted on a base structure indicated generally at 11. The pole unitcomprises a channel-shaped frame 13 of molded insulating materialrigidly supported on the base structure 11 by means of a bracket 15secured to the base structure 11 by means of bolts 17, the frame 13being secured to the bracket by bolts 19 (only one being shown). Thefront of the frame 13 is secured by bolts 21 to a bracket 23 which issecured to the base structure 11 by bolts 25.

Supported in the rear wall 27 of the insulating frame 13 is an upperterminal stud 31 and a lower terminal stud 33. The studs 31 and 33extend through suitable openings in the rear wall 27 of the frame 13 andhave contact blocks or feet 35 and 37 respectively, suitably secured totheir inner ends.

The upper block 35 supports the stationary contact latching positions.

structure indicated generally at 39 and a movable switch Y arm 41comprising a pair of spaced arms (only one being shown) is pivotallysupported by a pin 43 on `the lower contact foot 37. A movable contactstructure indicated generally at 45 is mounted between the movableswitch arms 41 for movement into and out of engagement with thestationary contact structure 39. The detail contact structure is fullydisclosed in copending application Serial No. 530,062, filed August 23,1955 by Robert C. Dickinson and Paul Olsson and assigned to the assigneeof the present invention. For this reason only a brief description ofthe contact structure is given herein.

The stationary contact structure 39 comprises a mainl stationary contact47 biased by a spring 49 for contact follow, and a stationary arcingcontact 51. The movable contact structure 45 comprises a main movablecontact 53 rigidly supported between the Contact arms 41 and a movablearcin; contact 55 biased by a spring 57 for contact follow.

The movable contact arm is connected by means of an operating rod 56 toan operating lever 58 forming part p 2,913,558 Patented Nov. 17, 1959 ofthe breaker operating mechanism mounted in the base structure 11. Therod 56 is pivotally connected by a pin 60 to the switch arms 41 and by apin 62 to the operating lever 58 which is pivotally supported on a pin64 in the base 11.

An operating linkage comprising toggle links 59, 61 and 63 is providedto releasably hold the operating lever 58 and consequently the movablecontact structure in the closed position and to operate the movablecontact structure to open and closed positions. The toggle link 59 ispivotally connected by means of a pivot pin 65 to the operating lever 58and the toggle link 63 is pivoted on a fixed pivot 67 supported on aframe 66 mounted on the base structure 11. The toggle link 61 ispivotally connected to the links 59 and 63, respectively, by knee pivotpins 69 and 71.

The linkages 59, 61, 63 comprise two toggles, one of which 59-61 may bedesignated as the tripping toggle and the other 61-63 as the closingtoggle. The tripping toggle 59-61 is normally slightly underset above aline drawn through the center of the pivot pins 65-71 and the closingtoggle 61-63 is normally underset below a line drawn through the centersof pivot pins 67-69. The closing toggle 61-63 is normally prevented fromcollapsing downward by a Support member 73 pivoted on a pin 75 supported-in the frame 66 and having a shoulder portion engaging under the kneepivot pin 71. The tripping toggle 597-61 is normally prevented fromcollapsing -by means of a main latch member 77 pivoted on a pin 78 inthe base 11 and connected by means of a link 79 to the knee pin 69 ofthe tripping toggle.

The main latch member 77 is held in latching position by an intermediatelatch lever 81 pivoted on the pins 75 and biased (by means not shown) tolatching positions. The intermediate latch lever carries at its upperend a latch roller 83 engaging a latch nose 84 on the -mainlatch 77 andat its lower end has a latching portion"85 normally engaging a latchroller 87 on a trip member 89 pivoted on a pin 91 in the frame 66. Thetrip member 89 is biased by spring means (not shown) to A bracket 97secured to the trip member'89 has a screw 99 adjustably mounted thereonfor cooperating with a trip device 100 shown -in the `form of a trippingelectromagnet.

The circuit breaker is tripped open by operation of the tripping magnet100 whose armature 101, upon energization of the magnet by a trippingimpulse, engages the screw 99 and rotates the trip membercounterclockwise causingthe latch roller 87 to release the intermediatelatchv 81. The latching engagement of the main latch 77 with the latchroller 83 is of the slip-off type and as soon as the intermediate latch81 is released it is moved to unlatching positions by the upward forceapplied to the/mainV latch through the link 79. The tripping toggle594-61 immediately collapses upwardly permitting counterclockwisemovement of the operating lever 58 and opening movement of the movablecontact structure. During the collapse of the'tripping toggle 59-61 aportion of the toggle link 61 engages and actuates the support member 73against the bias of a spring 110 to a non-supporting position, therebyfreeing the closing toggle 61-63. The closing toggle thereupon collapsesdownward and during its collapse resets Iand relatches the trippingtoggle 59-61.

The circuit breaker is closed by energization of a closing solenoid 111,the armature (not shown) of which is connected by means of a rod 113 tothe knee pin 71 of the closing toggle. When the solenoid 111 isenergized which may be effected either manually or automatically byclosing a suitable switch (not shown), the rod 113 is thrust upwardlystraightening the closing toggle 61-63,

and, since the tripping toggle 59-61 is now held in thrust transmittingposition, the operating lever 58 is moved clockwise to close thebreaker.

The opening movement of the movable contact structure is arrested byengagement of a surface 103 on the operating lever 58 with an abutment105 on the trame 66. Due to the mass of the movable contactrstructureand the high-speed of its opening movement, the moving contact structurehas a tendency to rebound after striking the abutment 105. Means areprovided to prevent such contact rebound. This means forms a part of agas-blast device puier indicated generally at 115 whichprovides a blastof air between the separating contacts. This putter device is describedin more detail in Lingal and Frink Patent No. 2,734,971 issued February14, 1956. The putter 115 comprises generally a chamber 117 deiined by acup-shaped base casting 119 extending across the three poles of thebreaker and integral with and supported by the bracket which supportsthe frame 13, and a diaphragm 121. The edge of the diaphragm 121 isclamped to a flange 123 on the casting 119 by clamp members 125 securedto the ange 123 by bolts 127. The center portion of the diaphragm 121 isclamped between two clamping members 129 and 131 which are secured onone end of a rod 133, the other end of which yis pivotally connected bya pivot pin 135 to the operating lever 58.

Threaded into an opening in the upper portion of the casting 119 is apipe 137 which at its upper end is provided with a suitable nozzle 139for delivering a blast of air to the contacts upon opening movement ofthe movable contact structure. The clamp members 129 and 131 are securedto the rod 133 on opposite sides of the diaphragm 121 by nuts 141 and143 which are threaded on the rod. A compression spring 145 compressedbetween the casting 119 and a washer 147 on the rod 133 biases the rodand the operating lever 58 in Contact opening direction.

The means for preventing the rebound of the moving Contact structurewhen it is stopped during an opening operation comprises a U-shapedmember 149 `rigidly clamped between the nut 143 and the clamp member 131and movable with the rod 133. The resilient side portions 151 of theU-shaped member 149 are tapered slightly outwardly as shown and areadapted when the breaker approaches open position to engage frictionmaterial 153 securely bonded to the facing sides of the clamp members125 with a wedging or squeezing action. As the breaker nears the openposition the flared portions 151 engage the friction material and thefriction generated thereby quickly and smoothly decelerates the openingmovement of the parts thus preventing any rebound of the movingstructure.

By changing the angle of the portions 151 or 153 or both, or byselecting a friction material having a greater or lesser coefiicient offriction more or less decelerating action can be obtained.

While the invention has been disclosed in accordance with the provisionsofthe patent statutes, it is to be understood that various changes andmodications may be made in the structural details without departing fromthe spirit of the invention.

I claim as my invention:

1. A circuit breaker having stationary contact means and a movablecontact structure having movable contact means thereon cooperatingwith'said stationary contacts to open and close said'bre'aaer and todraw an arc, operating mechanism operable to effect opening and closingmovement of said movable contact structure, a gas-blast device having aXed part and a part movable by said operating mechanism for assisting inthe extinction of said arc, spaced friction means mounted on said tiXedpart, and a member movable with said movable part of said gas-blastdevice having resilient portions disposed-to engage said spaced rictionmeans during an opening op eration to decelerate' the opening movementof the movable parts of said circuit breaker.

2. A circuit breaker having stationary contact means and a movablecontact structure having movable contact means thereon for cooperatingwith said stationary contact means to open and close said breaker andrtodraw The invention provides an anti-rebound device that is emcient andrequires few parts in addition to those used in devices without theanti-rebound device. No critical adjustment is required and suchcritical parts as pistons, cylinders, etc., are eliminated.

an arc, operating mechanism operable to move said movable contactstructure to open and closed positions, a gas-blast device comprisinga'diaphragm connected to be actuated by said operating mechanism toassist in the extinction of said arc, spaced friction means iixedlymounted on said gas-blast device, a member having resilient portionsthereon movable with Isaid diaphragm and engaging said spaced frictionmeans during an opening operation to decelerate the moving parts ofsaidcircuit breaker.

3. A circuit breaker comprising stationary contact means and a movablecontact structure having movable contact means thereon for cooperatingwith said stationary contact means to open and close said breaker and todraw an arc, operating mechanism including an operating lever operableto move said movable contact structure to open and closed positions, agas-blast device comprising a xed chamber and a diaphragm for assistingin the extinction of said arc, a rod connecting said operating lever andsaid diaphragm for actuating said diaphragm, spaced friction meansrigidly mounted on said xed chamber, and -a member mounted on saidrodand having resilient portions engageable with said spaced friction meansduring a closing operation to decelerate the moving parts of saidbreaker.

References Cited in the tile `oi this patent UNITED STATES PATENTS vMcCarty ..Oct. 5, 1926

